Device for interrupting electric currents



I Patented Au as, lea

UNITED srATas' PATENT OFFICE J'CtAlINES HENDRIGUS JOSEPHU S MAARTENS, O EINDHOVEH, NETHERLANDS, Afi- SIGNOE TO N. V. PHILIPS GLOEIL AMPENFABRIEKEN, 01 EINDHOVEN DEVICE FOR INTERRUPTING ELECTRIC CURRENTS Kc Drawing. Application filed July 23, 1926, Serial No. 124,554, and in the Netherlands October 7 1925.

This invention relates to a device for interrupting an electric current and more particularly to a device for igniting and extinguishing at regular intervals the light of an 5 electric lamp provided with a thermal interrupter.

The invention is based on the fact that sometimes the interrupter contacts are heated to such an extent that they become welded 1 together so that the working of the interrupter entirely ceases. This occurs in particular in the case of interrupters which serve to ignite and extinguish the light of an electric lamp at regular intervals. With such 15 a device the switching-on current is many times greater than the current required, for

' example, to heat tungsten filaments to a sufiicient incandescence,'such being aresult of the smaller resistance in the cold than in the warm state. The heavy switching-on current causes the interrupter contacts to become heated to a high temperature so that there is a risk of the said contacts welding together. v Now it has been found that when using special materials for the manufacture of the contacts of the interrupter, the said disadvantage can be obviated.- If the contacts consist on one side of nickel and on the other side of chrome-ironconsisting for example of 39 15-35% Cr. and 85-65% Fe., the welding together of the contacts does not occur. These materials are therefore very suitable for use in the manufacture of interrupter contacts which run the risk of welding together; al-' though by what means these contacts function is not to the purpose. The chrome-iron may contain admixtures of Mn, Ni, Co, C and 'Si without prejudicially influencing the working of the interrupter.

What I claim is A device for interrupting an electric current comprising a thermal interrupter and contacts being provided on said interrupter, one of said contacts consisting of nickel,

JOANRBS ammucus JOSEPHUS IIAARTENS.

whereas the other is made of chrome-iron. 

